1) Field of the Invention
The field of the present invention relates to lighting apparatus and systems as may be used in film, television, photography, and other applications.
2) Background
Lighting systems are an integral part of the film and photography industries. Proper illumination is necessary when filming movies, television shows, or commercials, when shooting video clips, or when taking still photographs, whether such activities are carried out indoors or outdoors. A desired illumination effect may also be desired for live performances on stage or in any other type of setting.
A primary purpose of a lighting system is to illuminate a subject to allow proper image capture or achieve a desired effect. Often it is desirable to obtain even lighting that minimizes shadows on or across the subject. It may be necessary or desired to obtain lighting that has a certain tone, warmth, or intensity. It may also be necessary or desired to have certain lighting effects, such as colorized lighting, strobed lighting, gradually brightening or dimming illumination, or different intensity illumination in different fields of view.
Various conventional techniques for lighting in the film and television industries, and various illustrations of lighting equipment, are described, for example, in Lighting for Television and Film by Gerald Millerson (3rd ed. 1991), hereby incorporated herein by reference in its entirety, including pages 96–131 and 295–349 thereof, and in Professional Lighting Handbook by Verne Carlson (2nd ed. 1991), also hereby incorporated herein by reference in its entirety, including pages 15–40 thereof.
As one example illustrating a need for an improved lighting effects system, it can be quite challenging to provide proper illumination for the lighting of faces in television and film, especially for situations where close-ups are required. Often, certain parts of the face must be seen clearly. The eyes, in particular, can provide a challenge for proper lighting. Light reflected in the eyes is known as “eye lights” or “catch lights.” Without enough reflected light, the eyes may seem dull. A substantial amount of effort has been expended in constructing lighting systems that have the proper directivity, intensity, tone, and other characteristics to result in aesthetically pleasing “eye lights” while also meeting other lighting requirements, and without adversely impacting lighting of other features.
Because of the varied settings in which lighting systems are used, the conventional practice in the film, commercial, and related industries is for a lighting system, when needed, to be custom designed for each shoot. This practice allows the director or photographer to have available a lighting system that is of the necessary size, and that provides the desired intensity, warmth, tone and effects. Designing and building customized lighting systems, however, is often an expensive and time-consuming process.
The most common lighting systems in film, commercial, and photographic settings use either incandescent or fluorescent light elements. However, conventional lighting systems have drawbacks or limitations which can limit their flexibility or effectiveness. For example, incandescent lights have been employed in lighting systems in which they have been arranged in various configurations, including on ring-shaped mounting frames. However, the mounting frames used in incandescent lighting systems are often large and ponderous, making them difficult to move around and otherwise work with. A major drawback of incandescent lighting systems is the amount of heat generating by the incandescent bulbs. Because of the heat intensity, subjects cannot be approached too closely without causing discomfort to the subject and possibly affecting the subject's make-up or appearance. Also, the heat from the incandescent bulbs can heat the air in the proximity of the camera; cause a “wavering” effect to appear on the film or captured image. Incandescent lighting may cause undesired side effects when filming, particularly where the intensity level is adjusted. As the intensity level of incandescent lights change, their hue changes as well. Film is especially sensitive to these changes in hue, significantly more so than the human eye.
In addition to these problems or drawbacks, incandescent lighting systems typically draw quite a bit of power, especially for larger lighting systems which may be needed to provide significant wide area illumination. Incandescent lighting systems also generally require a wall outlet or similar standard source of alternating current (AC) power.
Fluorescent lighting systems generate much less heat than incandescent lighting systems, but nevertheless have their own drawbacks or limitations. For example, fluorescent lighting systems, like incandescent lighting systems, are often large and cumbersome. Fluorescent bulbs are generally tube-shaped, which can limit the lighting configuration or mounting options. Circular fluorescent bulbs are also commercially available, and have been used in the past for motion picture lighting.
A major drawback with fluorescent lighting systems is that the low lighting levels can be difficult or impossible to achieve due to the nature of fluorescent lights. When fluorescent lights are dimmed, they eventually begin to flicker or go out as the supplied energy reaches the excitation threshold of the gases in the fluorescent tubes. Consequently, fluorescent lights cannot be dimmed beyond a certain level, greatly limiting their flexibility. In addition, fluorescent lights suffer from the same problem as incandescent lights when their intensity level is changed; that is, they tend to change in hue as the intensity changes, and film is very sensitive to alterations in lighting hue.
Typically, incandescent or fluorescent lighting systems are designed to be placed off to the side of the camera, or above or below the camera. Because of such positioning, lighting systems may provide uneven or off-center lighting, which can be undesirable in many circumstances.
Because of their custom nature, both incandescent lighting systems and fluorescent lighting systems can be difficult to adapt to different or changing needs of a particular film project or shoot. For example, if the director or photographer decides that a different lighting configuration should be used, or wants to experiment with different types of lighting, it can be difficult, time-consuming, and inconvenient to re-work or modify the customized lighting setups to provide the desired effects. Furthermore, both incandescent lighting systems and fluorescent lighting systems are generally designed for placement off to the side of the camera, which can result in shadowing or uneven lighting.
A variety of lighting apparatus have been proposed for the purpose of inspecting objects in connection with various applications, but these lighting apparatus are generally not suitable for the movie, film or photographic industries. For example, U.S. Pat. No. 5,690,417, hereby incorporated herein by reference in its entirety, describes a surface illuminator for directing illumination on an object (i.e., a single focal point). The surface illuminator has a number of light-emitting diodes (LEDs) arranged in concentric circles on a lamp-supporting housing having a circular bore through which a microscope or other similar instrument can be positioned. The light from the LEDs is directed to a single focal point by either of two methods. According to one technique disclosed in the patent, a collimating lens is used to angle the light from each ring of LEDs towards the single focal point. According to another technique disclosed in the patent, each ring of LEDs is angled so as to direct the light from each ring on the single focal point.
Other examples of lighting apparatus used for the purpose of inspecting objects are shown in U.S. Pat. Nos. 4,893,223 and 5,038,258, both of which are hereby incorporated herein by reference in their entirety. In both of these patents, LEDs are placed on the interior of a spherical surface, so that their optical axes intersect at a desired focal point.
Lighting apparatus specially adapted for illumination of objects to be inspected are generally not suitable for the special needs of the film, commercial, or photographic industries, or with live stage performances, because the lighting needs in these fields differs substantially from what is offered by object inspection lighting apparatus. For example, movies and commercials often require illumination of a much larger area that what object inspection lighting systems typically provide, and even still photography often requires that a relatively large subject be illuminated. In contrast, narrow-focus lighting apparatuses are generally designed for an optimum working distance of only a few inches (e.g., 3 to 4 inches) with a relatively small illumination diameter.
Still other LED-based lighting apparatus have been developed for various live entertainment applications, such as theaters and clubs. These lighting apparatus typically include a variety of colorized LEDs in hues such as red, green, and blue (i.e., an “RGB” combination), and sometimes include other intermixed bright colors as well. These types of apparatus are not well suited for applications requiring more precision lighting, such as film, television, and so on. Among other things, the combination of red, green, and blue (or other) colors creates an uneven lighting effect that would generally be unsuitable for most film, television, or photographic applications. Moreover, most of these LED-based lighting apparatus suffer from a number of other drawbacks, such as requiring expensive and/or inefficient power supplies, incompatibility with traditional AC dimmers, lack of ripple protection (when connected directly to an AC power supply), and lack of thermal dissipation.
It would therefore be advantageous to provide a lighting apparatus or lighting effects system well suited for use in the film, commercial, and/or photographic industries, and/or with live stage performances, that overcomes one or more of the foregoing disadvantages, drawbacks, or limitations.